Radio resource measurement techniques in directional wireless networks

ABSTRACT

Techniques for radio resource measurement (RRM) that support directionality, as well as scheduled media access techniques are described. For instance, a measurement request may be transmitted from a first device to a second device. This measurement request directs the second device to take one or more measurements of a wireless channel. Various characteristics for the one or more measurements may be included in the measurement request. For example, the measurement request may indicate at least one directional parameter and at least one timing parameter for the one or more measurements. In response to the request, the first device receives a measure report that includes measured values for each of the one or more measurements.

RELATED PARAGRAPH

This application is a continuation of U.S. patent application Ser. No.12/459,264, entitled “RADIO RESOURCE MEASUREMENT TECHNIQUES INDIRECTIONAL WIRELESS NETWORKS,” filed on Jun. 26, 2009.

BACKGROUND

Wireless networks, such as wireless personal area networks (WPANs),wireless local area networks (WLANs), and/or cellular telephony networksprovide for a wide array of mobile communications services. Currently,wireless networks are under development for the 60 GHz radio frequency(RF) band. Such networks intend to provide higher data rates, spatialreuse (enabled by the directional propagation properties of 60 GHzsignals), directional communications, enhanced interference mitigation,and network stability.

In addition, it is planned for 60 GHz wireless networks to employscheduled media access control (MAC) techniques, such as time divisionmultiple access (TDMA). However scheduled media access techniques aretypically not as robust as contention-based media access techniques. Forexample, carrier sense multiple access with collision avoidance(CSMA/CA) (which is currently employed in IEEE 802.11 networks) is oftenmore robust in handling transmission interference.

Thus, it is desirable to ensure network robustness when scheduled MACtechniques, such as TDMA, are employed. One way to promote robustnessinvolves the exchange of information between devices regarding thewireless environment. More particularly, such information provides forscheduled allocations that promote robust network operation.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference numbers generally indicate identical,functionally similar, and/or structurally similar elements. The drawingin which an element first appears is indicated by the leftmost digit(s)in the reference number. The present invention will be described withreference to the accompanying drawings, wherein:

FIG. 1 is a diagram of an exemplary operational environment;

FIG. 2 is a diagram of an exemplary transmission arrangement between twodevices;

FIG. 3 is a logic flow diagram;

FIG. 4 is a diagram of an exemplary channel quality histogram requestformat;

FIG. 5 is a diagram of an exemplary channel quality histogram reportformat; and

FIG. 6 is a diagram of an exemplary device implementation.

DETAILED DESCRIPTION

Embodiments provide techniques for radio resource measurement (RRM) thatsupport directionality, as well as scheduled media access techniques.For instance, embodiments may transmit a measurement request from afirst device to a second device that directs the second device to takeone or more measurements of a wireless channel. This measurement requestmay include various characteristics for the one or more measurements.For example, the measurement request may indicate at least onedirectional parameter and at least one timing parameter for the one ormore measurements. In response to the request, the first device receivesa measure report that includes measured values for each of the one ormore measurements.

Conventional RRM techniques do not support directionality and scheduledaccess (e.g., TDMA). For instance, the Institute of Electrical andElectronics Engineers (IEEE) 802.11k Amendment to the IEEE 802.11-2007Standard provides RRM schemes. However, these schemes were developedunder the assumption of a CSMA/CA MAC and an omni-directionaltransmission mode.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, appearances of the phrases “in oneembodiment” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments.

FIG. 1 is a diagram of an exemplary operational environment 100 that mayemploy the techniques described herein. This environment includes acentral controller device (PCP) 102, and multiple stations (STAs) 104a-d. These devices may be implemented in any combination of hardwareand/or software. In general operation, these devices may communicatewirelessly with each other. Moreover, in embodiments, these devices mayemploy multiple beams and/or directional transmissions.

PCP 102 performs various control operations, including resourceallocations for STAs 104 a-d. In particular, PCP 102 may manageresources within a repeating period called a TDMA frame (also known asBeacon Interval or Superframe). This may involve allocating time slotswithin the TDMA frame to STAs 104 a-d. Such allocations may employspatial reuse. More particularly, such allocations may overlap(completely or partially) in time.

In embodiments, allocations made by PCP 102 may be based on requestsreceived from STAs 104 a-d. In making such allocations, PCP 102 mayconsider characteristics regarding the wireless environment of STAs 104a-d. Details involving the determination of such characteristics areprovided below.

STAs 104 a-d may wirelessly communicate in accordance with resourceallocations performed by PCP 102. These communications may involvetransmissions between STAs 104. Also, these communications may involveexchanging transmissions with PCP 102. For example, PCP 102 may relaycommunications traffic between STAs. Further, PCP 102 may provide STAs104 a-d with access to one or more wireless networks (e.g., the Internetand/or wired telephony networks).

As described above, PCP 102 may consider characteristics regarding thewireless environment of STAs 104 a-104 d. To determine suchcharacteristics, PCP 102 may gather information from STAs 104 a-d. Moreparticularly, PCP 102 may transmit requests to STAs 104 a-d. Each ofsuch requests may direct the receiving STA to conduct particularmeasurements. In turn, the recipient STA conducts the measurement(s) andtransmits a report back to PCP 102. From such reports, PCP 102 mayperform resource allocations that consider factors, such as interferencemitigation, network stability, and so forth. For example, based on suchreceived report(s), PCP 102 may determine whether to make allocationsinvolving spatial reuse.

As example of such features, FIG. 1 shows PCP 102 sending measurementrequests 120 a and 120 b to STA 104 a and 104 b, respectively. Inresponse, STAs 104 a and 104 b send measurement reports 122 a and 122 bto PCP 102. These messages are shown for purposes of illustration, andnot limitation. Thus, messages may be sent to any combination of STAs104 a-d in any number and/or sequence.

In embodiments, a device (e.g., PCP 102) may make allocations based onthe amount of isolation among particular beams (as well as otherinformation). For example, a beam pairing must exhibit a sufficientlylow amount of isolation to support a wireless link. Further, the devicemay use such isolation information to establish multiple allocationsthat reuse resources (e.g., time and/or frequency and/or space). Moreparticularly, information included in such measurement reports may beused to establish a high degree of isolation between each allocation (sothat the interference is effectively managed). Examples of varyingisolation levels are illustrated below with reference to FIG. 2.

FIG. 2 is a diagram showing an exemplary wireless arrangement betweentwo devices. In particular, FIG. 2 shows a first station (“STA A”) and asecond station (“STA B”). These stations may be employed in the contextof FIG. 1 (e.g., each as one STAs 104 a-d).

Between these stations are multiple beams. For instance, FIG. 2 showsthat STA A provides transmit beams 202 a-c. Also, FIG. 2 shows that STAB provides receive beams 204 a-c. These features are shown for purposesof illustration and not limitation. Through beams 202 a-c, STA A mayengage in one or more directional transmissions. Similarly, throughbeams 204 a-c, STA B may receive transmissions from differentdirections.

FIG. 2 shows nine different pairings of transmit and receive beamsbetween STA A and STA B. Each of these pairings exhibits differentlevels of isolation. For instance, there is a low amount of isolationbetween beams 202 a and 204 a. This is because these beams aresubstantially aligned (or overlapping). In contrast, there is a highamount of isolation between beams 202 c and 204 c. This is because thesebeams are unaligned (or non-overlapping). In embodiments, such levels ofisolation may be determined through measurements performed by stations(e.g., STAs 104 a-d). Such measurements may be made in response torequests made by a controlling station (e.g., PCP 102).

Operations for the embodiments may be further described with referenceto the following figures and accompanying examples. Some of the figuresmay include a logic flow. Although such figures presented herein mayinclude a particular logic flow, it can be appreciated that the logicflow merely provides an example of how the general functionality asdescribed herein can be implemented. Further, the given logic flow doesnot necessarily have to be executed in the order presented unlessotherwise indicated. In addition, the given logic flow may beimplemented by a hardware element, a software element executed by aprocessor, or any combination thereof. The embodiments are not limitedto this context.

FIG. 3 illustrates an embodiment of a logic flow. In particular, FIG. 3illustrates a logic flow 300, which may be representative of operationsexecuted by one or more embodiments. This flow is described in thecontext of FIG. 1. However, this flow may be employed in other contexts.

At a block 302, a first device wirelessly sends a measurement request toa second device. This request directs the second device to perform oneor more measurements of a wireless channel. The first device may be acoordinator device for a wireless network (e.g., PCP 102), and thesecond device may be a user device (e.g., one of STAs 104 a-d). Inembodiments, this request may be a quality histogram request, asdescribed below with reference to FIG. 4. However, embodiments mayemploy other request formats.

The request may specify one or more characteristics for these one ormore measurements. For instance, the request may indicate particulardirectional and timing characteristics for the measurement(s). Examplesof directional characteristics include (but are not limited to) aparticular remote device to which the measurement(s) are to be directed,and a beam (e.g., a receive beam) through which the second device is toperform the measurement(s). Examples of timing characteristics include(but are not limited to) a measurement start time, a measurement periodduration, and a number of measurements to be taken during themeasurement period.

Further, the request may specify when the type of measurement(s) to betaken. Exemplary measurement types include a determination of an AverageNoise plus Interference Power Indicator (ANIPI), and/or determination ofa Received Signal to Noise Indicator (RSNI). Embodiments, however, arenot limited to these measurement types

At a block 304, the second device wirelessly receives the measurementrequest. Following this, at a block 306, the second device performs oneor more measurements in accordance with the request.

At a block 308, the remote device wirelessly sends a response (alsoreferred to as a measurement report) to the first device containing themeasurement(s). In embodiments, this response may be a quality histogramreport, as described below with reference to FIG. 5. However,embodiments may employ other response formats.

The first device receives the response at a block 310. Then, at a block312, the first device may make one or more resource allocations based oninformation provided in the response. As described above with referenceto FIG. 1, this may involve allocating one or more time slots within aTDMA frame. However, embodiments are not limited to TDMA media accesstechniques.

FIG. 4 is a diagram showing an exemplary format 400 of a channel qualityhistogram format request. This format includes multiple fields. Forinstance, a regulatory class field 402 provides information regardingregulated parameters, such as channel frequency, channel spacing, powerlimits, and so forth. A channel number field 404 provides informationregarding the channel for which measurements are to be taken.Embodiments may format fields 402 and 404 in accordance with Annex J ofthe IEEE 802.11k Amendment to the IEEE 802.11-2007 Standard. Each offields 402 and 404 may be one octet in size. However, other sizes may beemployed.

As shown in FIG. 4, format 400 further includes a STAID field 406 and aBeam ID field 408. These fields introduce directionality support for RRMmeasurements.

More particularly, STAID field 406 indicates a STA (e.g., by its MACaddress) towards which the RRM request applies. For example, if themeasuring STA is beamformed with the STA identified by STAID field 406,then the measurement shall be carried out directionally towardsidentified STA. In embodiments, STAID field 406 may be set to abroadcast ID (BcastID), in which case the measuring STA will do sothrough an omni directional pattern. STAID field 406 may be in variousformats. For example, in embodiments, STAID filed 406 indicates a MACaddress of a STA. FIG. 4 shows that STAID ID field 406 may be one octetin size, which may be an Association ID obtained by the STA once itassociated with the PCP. However, other types of identifiers and sizesmay be employed.

Beam ID field 408 indicates a beam for which the correspondingmeasurement request applies. For example, if source and destination STAshave multiple beams between them, Beam ID field 408 identifies one ofthem. A value of zero (0) in this field indicates that any beam may beused for this measurement. As indicated in FIG. 4, Beam ID field 408 maybe one octet in size. However, other sizes may be employed.

Measurement method field 410 indicates the method to be used by themeasuring STA in carrying the measurement request, as well as inreporting back to the PCP in the corresponding measurement report. Inembodiments, the conventions provided in the IEEE 802.11k Amendment tothe IEEE 802.11-2007 Standard may be employed. For example, when field410 is set to zero (0), Average Noise plus Interference Power Indicator(ANIPI) is designated. However, when this field is set to one (1),Received Signal to Noise Indicator (RSNI) is designated. Other values ofmeasurement field 410 may be reserved for other designations.Measurement method field 410 may be one octet in size. However, othersizes may be employed. Moreover, embodiments are not limited to ANIPIand RSNI. Thus, in embodiments, measurement method field 410 mayindicate other measurement types.

Measurement start time field 412 provides RRM support for scheduledaccess MAC protocols (e.g., TDMA). In the IEEE 802.11k Amendment to theIEEE 802.11-2007 Standard, no Measurement Start Time is defined. Rathera Randomization Interval is included which suits a CSMA/CA MAC protocol.However, for scheduled MAC protocols, a specific Measurement Start Timefield is required. Thus, measurement start time field 412 indicates atime when the requested measurement is to commence. In embodiments, avalue of 0 indicates that the requested measurement shall startimmediately. Measurement start time field 412 may be eight octets insize. However, other sizes may be employed.

Measurement duration field 414 indicates a duration of the requestedmeasurement. In embodiments, such duration may be either mandatory orpreferred. As indicated in FIG. 4, measurement duration field may be twooctets in size.

Number of time blocks field 416 provides a capability that isadvantageous for spatial reuse and interference mitigation, but which isnot currently supported in the IEEE 802.11k Amendment to the IEEE802.11-2007 Standard. In particular, this field indicates the number oftime blocks within the total Measurement Duration. A ratio between themeasurement duration and the number of time blocks (i.e., themeasurement duration divided by the number of Time blocks) provides aduration of each individual measurement to be conducted (also referredto as a measurement unit). As indicated in FIG. 4, field 416 may be oneoctet in size. However, other sizes may be employed.

In addition to the above fields, format 400 may include a field 418 (ofvariable size) to convey optional information sub-elements. Inembodiments, this field may employ the same convention, as provided bythe IEEE 802.11k Amendment to the IEEE 802.11-2007 Standard.

FIG. 5 is a diagram showing an exemplary format 500 of a channel qualityhistogram format report. This format includes multiple fields. Forinstance, regulatory class field 502 and channel number field 504provide information, as described above with reference to fields 402 and404 of FIG. 4. This information may be formatted as defined in Annex Jof the IEEE 802.11k Amendment to the IEEE 802.11-2007 Standard. Each offields 502 and 504 may be one octet in size. However, other sizes may beemployed.

STAID field 506 and Beam ID field 508 indicate the directionality aspectof the measurement report, as described above with reference to fields406 and 408 of FIG. 4. For instance, STAID field 506 indicates the STAtowards which the measurement applies and Beam ID field 508 indicatesthe beam that was used to perform the measurement. As indicated in FIG.5, STAID field 506 and Beam ID field 508 may each be one octet in size.However, other sizes may be employed.

Measurement method field 510, measurement start time field 512,measurement duration field 514, and number of time blocks 516 areemployed as described above with reference to fields 410-416 of FIG. 4.

FIG. 5 shows that format 500 includes multiple measurement fields. Inparticular, FIG. 5 shows measurement fields 518 ₁-518 _(N) thatcorrespond to each of N time blocks specified in the correspondingchannel quality histogram request. Each of measurement fields 518 ₁-518_(N) carries an actual measured value (e.g., an ANIPI value or anaverage RSNI value).

In addition to the above fields, format 500 may include a field 518 (ofvariable size) to convey optional information sub-elements. Inembodiments, this field may employ the same convention, as provided bythe IEEE 802.11k Amendment to the IEEE 802.11-2007 Standard.

FIG. 6 is a diagram of an implementation 600 that may be included in awireless device, such PCP 102 and/or STAs 104 a-d of FIG. 1. Thisimplementation, however, may be also employed in other contexts.Implementation 600 may include various elements. For example, FIG. 6shows implementation 600 including multiple antennas 602 a-c, atransceiver module 604, a host module 606, a measurement module 607, anda resource allocation module 608. These elements may be implemented inhardware, software, or any combination thereof.

Antennas 602 a-c provide for the exchange of wireless signals withremote devices. Although three antennas are depicted, any number ofantennas may be employed. Also, embodiments may employ one or moretransmit antennas and one or more receive antennas. Such multipleantenna arrangements may be employed for beamforming. For instance, aweight may be set in each antenna may such that the combined outputsignal provides a corresponding beam.

As shown in FIG. 6, transceiver module 604 includes a transmitterportion 610, and a receiver portion 612. During operation, transceivermodule 604 provides an interface between antennas 602 a-c and otherelements, such as host module 606, measurement module 607, and/orresource allocation module 608. For instance, transmitter portion 610receives symbols from such elements, and generates corresponding signalsfor wireless transmission by one or more of antennas 602 a-c. This mayinvolve operations, such as modulation, amplification, and/or filtering.However, other operations may be employed.

Conversely, receiver portion 612 obtains signals received by one or moreof antennas 602 a-c and generates corresponding symbols. In turn, thesesymbols may be provided to elements, such as host module 606,measurement module 607, and/or resource allocation module 608. Thisgeneration of symbols may involve operations, including (but not limitedto) demodulation, amplification, and/or filtering.

The signals generated and received by transceiver module 604 may be invarious formats. For instance, these signals may be modulated inaccordance with an orthogonal frequency division multiplexing (OFDM)scheme or a Single Carrier (SC) scheme. However, other schemes andformats (e.g., QPSK, BPSK, FSK, etc.) may be employed.

To provide such features, transmitter portion 610 and receiver portion612 may each include various components, such as modulators,demodulators, amplifiers, filters, buffers, upconverters, and/ordownconverters. Such components may be implemented in hardware (e.g.,electronics), software, or any combination thereof.

The symbols exchanged between transceiver module 604 and other elementsmay form messages or information associated with one or more protocols,and/or with one or more user applications. Thus, these elements mayperform operations corresponding to such protocol(s) and/or userapplication(s). Exemplary user applications include telephony,messaging, e-mail, web browsing, content (e.g., video and audio)distribution/reception, and so forth.

Moreover, in transmitting and receiving signals, transceiver module 604may employ various access techniques. For example, transceiver module604 may employ a scheduled MAC technique, such as TDMA. Embodiments,however, are not limited to such techniques.

Measurement module 607 may perform measurements of wireless resources.Such resources may be specified in accordance with requests received(through transceiver module 604) from a remote device, such as PCP 102or an IEEE 802.11 access point (AP). As described above, suchmeasurements may be of average noise plus interference power (to providean ANIPI), and/or of received signal to noise Indicator (to provide anRSNI). However, embodiments are not limited to these measurements. Thus,other wireless channel measurements (e.g., measurements involving anycombination of signal power, interference power, and/or noise power) maybe made.

Measurements made by measurement module 607 may be from hard symbolsreceived from transceiver module 604 (e.g., based on a bit error ratedetermined through comparison with a predetermined sequence). Also, suchmeasurements may be based on soft symbols generated by transceivermodule 604 from received wireless signals. Moreover, such measurementsmay be generated from un-demodulated signals provided by transceivermodule.

In addition, measurement module 607 may generate a report message thatindicates such measurements. This report may be transmitted to theremote device through transceiver module 604.

In embodiments, resource allocation module 608 may perform resourceallocation techniques described herein. For example, based on receivedmeasurements, allocation module 608 may allocate portions of acommunications resource (e.g., time slots within a TDMA frame). Suchallocation may include employ reuse that where sufficient isolationexists. Such isolation may be determined through measurements receivedfrom remote stations (through transceiver module 604). Allocations maybe communicated to remote devices (through transceiver module 604) incontrol messages.

As described herein, various embodiments may be implemented usinghardware elements, software elements, or any combination thereof.Examples of hardware elements may include processors, microprocessors,circuits, circuit elements (e.g., transistors, resistors, capacitors,inductors, and so forth), integrated circuits, application specificintegrated circuits (ASIC), programmable logic devices (PLD), digitalsignal processors (DSP), field programmable gate array (FPGA), logicgates, registers, semiconductor device, chips, microchips, chip sets,and so forth.

Examples of software may include software components, programs,applications, computer programs, application programs, system programs,machine programs, operating system software, middleware, firmware,software modules, routines, subroutines, functions, methods, procedures,software interfaces, application program interfaces (API), instructionsets, computing code, computer code, code segments, computer codesegments, words, values, symbols, or any combination thereof.

Some embodiments may be implemented, for example, using a storage mediumor article which is machine readable. The storage medium may store aninstruction or a set of instructions that, if executed by a machine, maycause the machine to perform a method and/or operations in accordancewith the embodiments. Such a machine may include, for example, anysuitable processing platform, computing platform, computing device,processing device, computing system, processing system, computer,processor, or the like, and may be implemented using any suitablecombination of hardware and/or software.

The storage medium or article may include, for example, any suitabletype of memory unit, memory device, memory article, memory medium,storage device, storage article, storage medium and/or storage unit, forexample, memory, removable or non-removable media, erasable ornon-erasable media, writeable or re-writeable media, digital or analogmedia, hard disk, floppy disk, Compact Disk Read Only Memory (CD-ROM),Compact Disk Recordable (CD-R), Compact Disk Rewriteable (CD-RW),optical disk, magnetic media, magneto-optical media, removable memorycards or disks, various types of Digital Versatile Disk (DVD), a tape, acassette, or the like. The instructions may include any suitable type ofcode, such as source code, compiled code, interpreted code, executablecode, static code, dynamic code, encrypted code, and the like,implemented using any suitable high-level, low-level, object-oriented,visual, compiled and/or interpreted programming language.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not in limitation. For example, the techniquesdescribed herein are not limited to IEEE 802.11 networks. Thus, thesetechniques may be employed in other networks, such as ones that employany combination of directional transmissions, reuse, and/or scheduledmedia access techniques.

Accordingly, it will be apparent to persons skilled in the relevant artthat various changes in form and detail can be made therein withoutdeparting from the spirit and scope of the invention. Thus, the breadthand scope of the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

The invention claimed is:
 1. A method, comprising: transmitting ameasurement request from a coordinator device to a station device, themeasurement request directing the station device to perform an isolationmeasurement directed toward a device of one or more beams of amillimeter wave wireless channel, wherein the isolation measurementcomprises a measurement of an amount of isolation between the one ormore beams; receiving at the coordinator device, a response to therequest, the response comprising an isolation value corresponding to themeasurement; and allocating a wireless resource based at least on theisolation value, wherein the measurement request includes at least onetiming parameter for the measurement and an identifier of the devicetowards which the station device is to direct the measurement.
 2. Themethod of claim 1, wherein allocating the wireless resource comprisesallocating one or more time slots within a time interval.
 3. Anapparatus, comprising: a transceiver module to exchange wireless signalswith one or more remote devices; and a resource allocation module to:transmit a measurement request to a remote device through thetransceiver module, the measurement request directing the remote deviceto take one or more isolation measurements directed toward a device ofone or more beams of a millimeter wave wireless channel, wherein the oneor more isolation measurements comprise measurements of an amount ofisolation between the one or more beams; receive a measure report inresponse to the request, the report comprising measured isolation valuesfor each of the one or more measurements; and allocating a wirelessresource based at least on the isolation value, wherein the measurementrequest includes at least one timing parameter for the measurement andan identifier of the device towards which the station device is todirect the measurement.
 4. The apparatus of claim 3, wherein thewireless resource includes a time slot within a time interval.
 5. Theapparatus of claim 3, wherein the at least one timing parameter includesa start time for the one or more measurements.
 6. A non-transitorycomputer readable medium including instructions stored thereon, whichwhen executed by one or more processor(s), cause the device to performoperations of: transmitting a measurement request from a coordinatordevice to a station device, the measurement request directing thestation device to perform an isolation measurement directed toward adevice of one or more beams of a millimeter wave wireless channel,wherein the isolation measurement comprises a measurement of an amountof isolation between the one or more beams; receiving at the coordinatordevice, a response to the request, the response comprising an isolationvalue corresponding to the measurement; and allocating a wirelessresource based at least on the isolation value, wherein the measurementrequest includes at least one timing parameter for the measurement andan identifier of the device towards which the station device is todirect the measurement.
 7. The non-transitory computer readable mediumof claim 6, wherein allocating the wireless resource comprisesallocating one or more time slots within a time interval.